Enzymatic synthesis and evaluation of new novel omega-pentadecalactone polymers for the production of biodegradable microspheres.

Two novel co-polymers based on omega-pentadecalactone were enzymatically synthesized by a combination of ring-opening polymerization and polycondensation. Modified literature procedures enabled the production of the semi-crystalline materials with suitable molecular weights and melting characteristics. Microspheres were produced using an emulsion solvent evaporation method over a range of variables including manufacturing temperature, stirring speed and duration, surfactant concentration, continuous and disperse phase volume and polymer amount to establish how each variable affected the morphological characteristics of the microspheres. Results demonstrated that changes in emulsion viscosity influenced microsphere size. For polymer SH-L333, the microsphere surface was either smooth or porous depending on the manufacturing temperature used. For polymer SH-L334 the microsphere surface was rough or porous regardless of manufacturing temperature. This was possibly due to several combined factors including molecular weight and the greater hydrophilic nature of SH-L334. These new polymers have the potential for the manufacture of drug-loaded biodegradable microspheres for modified release drug delivery.